Twins Not looking good for me

I am pregnant with twins I'm still early I have had 2 vaginal scans and there is 1 HB from one baby and not from the other I have layer in hope for 3 weeks now I had a scan Friday last week and had already organised to see my Dr today which I did my hcg levels were 26000 2 weeks ago and not sure what they were this time I didn't like to ask... but Dr said have dropped which straight away sent alarm bells to me. Then I was told Twin A its HB is low I was shocked as to how low (I sat there with a brace face,) then he told me Twin B will prob stop growing and I will miscarry, so I have to have some tests and see a specialist at the hospital and then repeat the scan on the 4th Dec. This wasn't planned but was the BEST ever News I could ask for now looks like things are going to hit me hard so I won't know till I see specialist waiting for them to call me with app date. I had a miscarriage back in 2015 as well this was so heart breaking for me as it is to all mums. I just can't believe it

There is a chance Twin B may make it I'm

Not so sure with the HB rate